1. Field of the Invention
The invention relates to a workpiece mounting for a material removal working machine according to the preamble of claim 1.
2. Description of the Prior Art
In working machines, such as, for example, drilling and milling machines and in particular laser working machines, the workpiece is chucked onto a workpiece mounting for the working. In order to position the workpiece with respect to the working tools, or with respect to the laser beam, and to generate the working advance, it is known to chuck the workpiece onto a circular mounting plate which is supported rotatably in a horizontal plane and is movable in this horizontal plane by means of a conveying unit. The mounting plate is herein supported rotatably by means of a pivot bearing which is attached on the conveying unit and is moved by means of it. In order to be able to work heavy work pieces, a corresponding high loading capacity of the mounting plate and its pivot bearing is necessary. The bearing is therefore constructionally expensive and has a high weight. Accordingly, the conveying unit, which is conventionally movable in the X and Y axes, must be laid out to be highly loadable.
Such expensive workpiece mountings are justified for series productions. The cost of working of single workpieces, for example the laser working of injection molding form tools, however, is excessively increased due to such workpiece mountings.
The invention is therefore based on the task of providing a workpiece mounting which is constructed cost-effectively and also is suitable for heavy workpieces.
This task is solved according to the invention through a workpiece mounting with the characteristics of claim 1.
Advantageous realizations of the invention are specified in the dependent claims.
The essential concept of the invention comprises chucking the workpiece onto a mounting plate, which, air-supported on a horizontal table surface, is freely movable, in particular can also be rotated about its vertical axis. In the desired rotary position the mounting plate is clamped on the conveying unit. The conveying unit is preferably formed of two linear guidances such that the mounting plate clamped on the conveying unit can be moved under control in the X and Y direction by means of the conveying unit.
Based on the air support of the mounting plate on the table surface, the mounting plate is movable free of friction even if heavy workpieces, of, for example, up to 200 kg are chucked. With the clamping disengaged, the mounting plate can be moved, in particular also be moved manually, on the table surface. The mounting plate can in particular also be rotated in order to orient the chucked workpiece in the X and Y directions of the linear guidances of the conveying unit. After rotating the mounting plate for angular positioning, the mounting plate is clamped on the conveying unit. The linear advance in the X direction and the Y direction for the working can now be carried out by means of the conveying unit. Since the mounting plate is air-supported, it can be moved free of friction by the conveying unit such that the conveying unit only needs to apply low displacement forces even with heavy workpieces. The conveying unit can therefore be laid out simply and cost-effectively.
Depending on the requirements, the linear guidances of the conveying unit can be driven by motor or manually, wherein, in the case of a motor drive, a joy stick control or also a CNC control can be used.
In a useful implementation the mounting plate is clamped at its circumference on the conveying unit. For this purpose the mounting plate can comprise a circumferential flange, which is grasped by a clamping device of the conveying unit. A simple implementation is obtained thereby that the conveying unit comprises a circular-arc form seat, which extends under the circumferential flange of the mounting plate, wherein clamping means, for example, in the form of clamping jaws, clamp the circumferential flange securely on this seat.